Electric-switch contact



March 24, 1931. Q ENGSTROM 1,797,948

ELECTRIC SWITCH CONTACT Filed March 5, 1930 Inventor- Hem g O E gs'L-Pom,

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PatenbdMuJ-t, 1931 UNITED STATES PATENT OFFICE may 9. mms'rnox, or 33111612031, oommcnco'r, assrenoa 011mm ELEG- rmcoonm, A ooaronarrox or NEW YORK ammo-amen common a lication fled mas, mo. semi R0. 438,461.

The present invention relates to snap switch movements, and has for its object the provision of an improved construction which is simple, reliable and cheap to manufactureand assemble.

The invention is particularly well adapted for use in sockets for electric incandescent lamps and will be described in that connection, but it is also useful in switch mechio anisms designed for other purposes.

For a consideration of what I believe to be novel and my invention, attention is directed to the accompanying description and the claims appended thereto.-

In the attached drawing, Fig. 1 is a perspective view of a lamp socket with certain of the parts broken away; Fig. 2 is a view in vertical section; Fig. 3 is an exploded view; Fig.4 is a bottom plan view; Figs. 5 80 and 6 are perspective views of the terminal members, and Fig. 7 is a view of the center contact.

4 indicates a screw threaded shell adapted to receive the cooperating part of an incan- 36 descent lamp. The shell has an inturned flange 5 at its upper end which is attached by suitable means as eyelets or rivets 6, 7,

and 8 to a thin disk 9 of tough insulating material of any suitable material. This disk supports on its upper side a pair of terminal contact members 11 and 12. The member 11 shown in Fig, 5 is insulated from the shell 4 and other parts and has a base 13 which is secured to the disk 9 by a rivet 8*, Fig. 4, the metal of the inturned flange 5 being cut away in the region thereof as indicated so as to separate the metal parts by insulation. It is also provided with a vertical-contact plate 14 arranged at right angles to the base and to the vertical part 15 which receives the binding screw 16. The vertical part has a limited amount of spring or resilience and the extreme upper .end is inturned to form a hook 17 which engages and holds a cap or block of insulation, as will appearlater. The base is also provided with a short prong or projection 18 which enters a small hole in the fibre or other insulating disk 9 to prevent the member from turning about the rivet 8 as a pivot. The

prong is made of less length than the thick- 9 ness of the disk 9 so as to ensure pro er insulation between the member and the ange 5 of the shell.

The member 12, shown in Fi 6, has a base 19 which is secured to the dis 9 and the flange 5 of the shell by the rivet 7 Fig. 4, which rivet also establishes electrical communication between the shell and the member. It is also provided with a prong 21 which extends into the disk 9 to prevent the base from turning about the rivet 7 as a piv- 0t. Rising from the base is a vertical part 22 which receives a binding screw 16' for a circuit wire. This part also has a limited amount of spring or resiliency and the extreme upper end is inturned to form a hook 23 which with the hook 17 engage and hold a cap or block of insulation as will appear later.

The center contact 25, best shown in Fig. 7 and also in Fig. 4. comprises a spring part or tongue 26 that is centrally located within the shell and carried by the insulating disk 9. It has a pair of prongs or rivets 27 which secure it to the disk and also a flat contact element 28 whicl: projects through the disk from the under side thereof and rises above it. \Vhen assembled the part 14 of member 11 and part 28 of the center contact are aligned in the same transverse plane as shown in Fig. 3, and it is through theseparts that the circuit of the lamp or otherv current receiving device is made and broken.

' In addition there is mounted on the disk 9 a pair of metal guides 29 and 30. Guide 29 is L-shaped and riveted to the disk 9 and at its upper end is provided with a square shouldered recess 31 to receive and guide the actuator 32. The guide 30 is U-shaped and also riveted to the "disk 9. The outer part of the guide is also provided with a recess' '33, the

. insulating V of the spring move back and forth between iii piece which comprises an inverted U- shaped piece of spring wire bent to form a loop or turn 36 at its upper end, with the lower ends of the legs'terminating in wholly or partly rounded ends to enlarge the contacting surfaces which engage the contacts 14 and 28 to close the circuit, and the stop 34 when the circuit is broken. The upper end of the spring rests in a small socket 37 which forms a pivotal support therefor, Fig. 1, said socket being formed in the under side of the lock or cap 38. The lower ends the contacts and stops by a swinging or pendulum movement, with the socket 37 forming the pivotal point.

The actuator 82 comprises a cam plate 32 which has insulating end buttons 39 which project through the enclosing shell 40 which may be made of metal or of insulation as desired. In the center of the cam plate which connects the buttons is a rectangular enlargement having a central opening the walls of which diverge in opposite directions from the opposed points 41. In other words, the walls of the cam plate define two triangular opposed openings with the point of greatest restrict-ion in line with the points 41. The legs of the spring or contact member 35 extend through the opening as best shown in Fig. 1. -As the actuator is moved by a reciprocating movement from one of its positions to the other said legs are squeezed or moved toward each other until they pass the points 41 after which they are automatically released and move bodily by a snap action so that the lower ends 36* are caused to engage either the contacts 14 and 28 or the stop 34 as the case may be. At the start the movement of the actuator due to the inclined walls of the cam plate causes the legs to move slightly towardeach other without breaking the circuit at the spring ends 36, which has the effect of wiping the stationary contacts to a sufficient extent to keep them clean and bright, thus ensuring good contact evcn after long periods of use.

The cap or block 38 may be made of porcelain, molded composition or other suitable insulating material. It has two diametrically opposed slots or openings 44: to receive the inner ends of the push buttons 39 and also a pair of shouldered projections 45 which hold the cam plate 32 from moving upwardly out of the guides 29 and 30 which it would otherwise do. This lifting tendency is due to the slanting legs of the spring 35. The cap is also provided with a second pair of diametrically opposed recesses or slots 46 at right angles to the slots or recesses 44. and in which the terminal members 11 and 12 are located. The upper ends of the slots have beveled surfaces 47 with'which the inturned ends 17: and 23 of the terminal members engage and by their spring action hold the cap or block in place. To remove the cap it is only necessary to spring the members outwardly when the cap is released. By this simple expedient the entire working parts of the switch are exposed. From this it also follows that the assembly of the parts is a simple matter.

The parts thus far described are enclosed in the usual metal shell 40 and metal cap 48, both of which have or may have the usual insulating linings 49. The cap has a collar 50 through which the circuit wires pass to the termlnal members.

My improved construction has the advantage of simplicity of construction and low cost., The contacts, terminal members, etc., are all mounted on the disk 9 to which the screw shell" 4: is also attached. The ac.- tuator 32 and the ole piece or spring 35 are assembled from a ove and are held by the cap or block which latter is held by the ends of the terminal members 11 and 12. It is thus possible to get at the movingparts without dificulty and without the use of special tools of any kind. This means that the switch can easily be repaired when necessary, and the fact that the stationary parts are riveted to the disks means that there is little or no chance for them to work loose.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a switch movement, the combination of a divided insulating support, stationary contacts carried by one part of the support, a spring contact member pivotally: supported at one end by the other part of the support, a cam plate having walls which are inclined in opposite directions from a common point, said walls engaging the member for moving it, and a means for reciprocating the cam plate to cause the contact member to move with a snap action from one of its positions to the other.

' 2. In a switch movement, the combination of a divided insulatingsupport, means for uniting the parts thereof, stationary contacts carried by one of said parts, a U-shaped spring contact member which is pivotally supported by the other of said parts, a cam plate having an opening therein through which the contact member extends the walls of which define two triangular opposed communicatingopenings, and a means for reciprocating the plate to cause the member to move with a snap action fromone of its positionsto the other.

3. In a switch movement, the combination of a divided insulating support, stationary contacts carried by one part of the support, a spring contact member loosely pivoted inthe other part of the support, a cam plate having an opening therein through which the contact member extends, said cam having surfaces which impart to the member a snap action, guides for the cam plate which are carried b the same part of the support which carries the stationary contacts, and means for reciprocating the cam plate.

4. In a switch movement, the combination of an insulating base, stationary contacts and also metal guides carried thereby, an insulating cap for the base which has a central socket in its under side and also projections which act as guides, a reciprocating cam plate situated between the guides on the base and cap and which has a central opening, an inverted U-shaped spring contact member which is loosely pivoted in the socket and extends through the opening in the cam, and a means for reciprocating the cam.

5. In a switch movement, the combination of an insulating base, stationary contacts. mounted on the upper side of the base, a

screw threaded shell secured to the under side of the base, and also a center contact which I is electrically connected to one of the stationa-ry contacts, terminal members secured to the upper side of the base, one of which is connected to a stationary contact, a sepa rable cap which has a central socket on its under side and which is held in fixed position by the terminal members, a reciprocating cam plate which has a central opening,

means for actuating it, and an inverted U-shaped spring contact which is seated in the socket at its upper end, the legs of said contact extending through the opening for engagement with the stationary contacts when the cam is moved to one of 1ts posltlons.

6. In a switch movement, the combination of a two part insulating support, one of which has a socket, a pair-of stationary contacts carried by the other support, an inverted U- shaped spring contact member, the closed end of which is loosely seated in the socket, a cam plate for swinging the member to-andfro which is arranged to squeeze the legs of the member toward each other for a portion of the stroke of the member and then to release them, and means for actuating the cam plate. v

7. In a switch movement, the combination of an insulating base, an insulating cap therefor which has a socket, stationary contacts carried by the base, an inverted U-shaped spring contact member, the closed end of which is seated in the socket, the open ends being arranged to engage the stationary contacts, a cam plate for moving the lower ends of the spring into and out of engagement with the stationary contacts, means for actuating the cam plate, and terminal members mounted on the base having hooks at their upper ends which engage and between them hold the cap in position.

In Witness whereof, I have hereunto set my hand this third da of March, 1930.

HE RY O. ENGSTROM. 

